For many applications of silver halide photographic materials, dimensional stability is of utmost importance. Although polyester based plastic films can be used to produce photographic materials showing good dimensional stability, it is for speciality applications, e.g. photomicrography, some graphic arts application, photofabrication of PCB (printed circuit boards), etc, still preferred to use silver halide photographic materials coated on glass. Also in application where the material has to have high thermal stability, the use of a glass support is preferred over the use of a plastic film support. An example of an application where high thermal stability is needed is the manufacture of LCD's as described in EP-B 396 824 and EP-A 615 161. In the manufacture of colour filters for the production of colour LCD's the optical isotropy of glass (most polymer films are optically anisotropic, i.e. show birefringence) is an advantage.
Applying layers on glass plates in a continuous process is described in EP-A 716339. Said application discloses a process for applying various layers on a glass support in a continuous applying machine characterized in that (i) the thickness of the glass support is lower than 1.2 mm and (ii) the glass support has a failure stress (under tensile stress) equal or higher than 1.times.10.sup.7 Pa and an elasticity modulus (Young's modulus) equal to or lower than 10.times.10.sup.10 Pa. However said materials still show two distinct disadvantages. First of all said material can not be wound on a small core with a sufficient safety factor to avoid premature breaking and secondly the strength of said glass is to low for use in greater dimensions such as is needed for LCD's.
Chemical strengthened float glass is known which has greater strength than normal float glass. EP-A 286018 discloses a support consisting of chemically straightened glass. However said glass still cracks from the border out. JP-58-208728 describes a liquid crystal color display between substrates each made of borosilicate glass coated with a silica film. However said glass still cracks from the border out. JP-57-205343 discloses the preparation of tempered glass by subjecting the glass to heat treatment at a fixed temperature raising rate and ion exchange treatment, and forming a metallic film. However said glass still cracks from the border out. JP-58-156554 describes the prevention of the deterioration of the thin film formed on the surface of a glass substrate, by reducing the content of sodium oxide in the surface layer of a borosilicate glass containing sodium oxide by ion exchange treatment. However said glass still cracks from the border out. However the literature is silent about the solution for the problem of winding glass upon small cores.
Furthermore in chemical hardened glass there still originates cracks at the border of said glass.